WASHINGTON, Sept 1 (Reuters) - A senior U.S. Congressman from Texas has come out in full support of the United States lifting the 40-year old ban on crude oil exports, putting him at odds with fellow House Republicans wary of weighing in on the controversial issue.

Rep. Joe Barton, who until now has maintained a relatively neutral public stance on a topic that has divided Republican members of the House energy and commerce committee, told Reuters in a statement that the time was right for the United States to overhaul its long-standing restrictions on exporting crude oil.

"The shale revolution has changed the energy landscape in our country. It is time to change our laws to match this new reality," said Barton, who represents Texas' sixth Congressional district just southwest of Dallas, several hundred miles from the burgeoning oil patches of the Eagle Ford and Permian.

"I'm in favor of overturning the ban on crude oil exports."

Barton chairs the energy task force of the Republican Study Committee, which will continue to debate the ban and issue position papers.

It is the most definitive statement that the former chairman of the House energy committee has made outside of private meetings on the subject, said Sean Brown, Barton's press secretary.

Barton is "happy to discuss the issue" with House colleagues and some in the business community who may disagree, Brown said.

The outspoken lawmaker, in office since 1985, joins other powerful politicians including Senate energy and natural resources committee chair Mary Landrieu of Louisiana and ranking member Lisa Murkowski from Alaska in backing definitive action on exports. They want to move beyond the incremental measures that are already allowing a growing trickle of shale oil to find new markets, such as South Korea and the Netherlands.

Although several research reports have found that exporting the glut of shale oil would ultimately lower U.S. and global fuel prices, rather than raise them, U.S. public opinion remains divided on the issue.

Meanwhile some environmentalists are beginning to rally against overseas sales because they fear it will encourage even more fracking.

ON THE FENCE

Barton's previous public comments on the issue were more careful.

"I can debate either side of that," he said at an event in February.

Barton said there was a strong economic argument to lift the export ban, but such a decision might roil environmentalists, provoking another political fight in a divided Congress.

Rep. Fred Upton, a Michigan Republican who succeeded Barton as the energy committee chair, has not yet taken a position on the ban.

"The committee is still studying the issue. We will continue to conduct analysis the remainder of the year and into next Congress," committee spokeswoman Charlotte Baker said.

With mid-term elections looming, some lawmakers want to avoid discussing crude exports altogether as it may raise fears among voters that a policy change would drive up gasoline prices.

Some lawmakers in Texas and on the east coast are at odds with others because oil refiners in their districts have benefited from the crude oil ban and oppose a policy change.

In March, four U.S. oil refiners including Alon USA Energy and PBF Energy formed anti-export group Consumers and Refiners United for Domestic Energy, or CRUDE, a lobby with the goal of preventing a hasty reversal of the ban.

Barton's statement is significant because some prominent Republicans have not taken a firm stance on the issue yet, said Kevin Book, an analyst with Clear View Energy Partners.

"The reason he probably hasn't been more vocal is because the rank and file is terrified," he said.

But Barton has little to lose by backing crude exports, according to Book, since his district is home mainly to oil producers.